1. Field of the Invention
This invention relates to joining by fusion of members made of thermoplastic material and in particular to the joining by fusion of thermoplastic members comprising frames for windows, doors, and like structures.
2. Prior Art Statement
It is known in the art to provide a method of joining by fusion members made of thermoplastic material such as thermoplastic frame members for windows, doors, and the like which carry and support glass panes, screens, and the like. In particular, a known method of joining such members comprises the steps of forming edge means on the members, aligning and clamping said edge means and members against an alignment plate, withdrawing the plate to define a controlled gap therebetween, heating a blade to a predetermined temperature and inserting same in the gap, urging the said edge means against the blade in a controlled manner to heat same and portions of the members adjoining the said edge means and define plasticized edge portions, retracting the blade, moving the members to place said plasticized edge portions against each other in a controlled manner to a preset position to provide fusion thereof, and holding the members and plasticized edge portions stationary at the preset position while allowing cooling and solidification thereof.
It is also known in the art to provide an apparatus for joining members made of thermoplastic material and having edge means to be joined formed on said members, with said apparatus comprising an alignment plate adapted to be supported in an alignment position, carrier means for said members, said carrier means enabling aligning and clamping the said edge means and members against the alignment plate, means for withdrawing the plate to define a controlled gap therebetweeen, a blade for heating the said edge means, means for heating the blade to a predetermined temperature, means for inserting the blade in the gap and retracting same therefrom, positioning means for said carrier means enabling urging of the said edge means against the blade in a controlled manner to enable heating same and portions of the members adjoining the said edge means and define plasticized edge portions, the said means for inserting and retracting being adapted to retract the blade upon heating thereof, said positioning means also serving to move said carrier means and members and their plasticized edge portions against each other in a controlled manner to a preset position to provide fusion thereof, and said carrier means and positioning means being adapted to hold said members and plasticized edge portions stationary at said preset position while allowing cooling and solidification thereof.
It is also known in the art to provide a device for heating edge means of members made of thermoplastic material and portions of said members adjoining said edge means upon urging said edge means against said device to define plasticized edge portions which are adapted to be joined by fusion, said device comprising, a support, a blade carried by said support, and means carried by said support for heating said blade to a predetermined temperature to enable heating said edge means and said portions of said members adjoining said edge means upon urging said edge means against said blade, said plasticized edge portions being adapted to be joined by said fusion upon moving same against each other and allowing cooling thereof.
However, previous methods, apparatus, and devices including the ones disclosed above have deficiencies which preclude joining of thermoplastic members by fusion in a fast and efficient manner and which preclude such joining of such members with minimum flashing and carbonization of the thermoplastic material comprising same.